Arteriovenous fistulae are artificial connections between the artery and vein in the arm which allow needles to be inserted for haemodialysising patients wit kidney failure. Occasionally severe debilitating pain can arise from these fistulae for which no cause can be found. Such pain can be very difficult to treat. Many commonly used used painkillers are known to cause significant side effects in patients with renal failure (drowsiness, confusion etc.